matic J is a highly friction modified ATF in a synthetic base oil. It allows the ultra smooth shifting that you experience and the ultra smooth torque converter lockup too.
its quite long life ATF, approximately first change is at 100,000 kms.
other highly friction modified atfs are, toyota tiv, toyota WS, honda dw1/z1 (useless ATF), nissanmatic J, Mercedes Benz 236.10, 236.12, 236.14, subaru HF ATF... there are tons of them out there.
I beleive meguin sell an ATF that is compatible with nissanmatic J. only change if your mileage has exceeded the change interval, Dont just pour in the plain dexron clone ATF called ZIC III because the shopkeeper says so.